For the SNCF, the summer period is always delicate, the strong heat being able to affect the rail network and disrupt train traffic. Last year, the government went so far as to advise against taking the train during a heat spell in late July, fearing incidents. It was in Belgium that infrastructure had suffered the most, particularly affecting Thalys high-speed trains.
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We are not there this year. But the SNCF planned to activate its plan on Friday to cope with periods of high heat, which notably provides for reinforced monitoring of equipment and infrastructure. From 12:00 p.m. to 8:00 p.m., for now.
The rails are particularly sensitive during heat waves, especially as they accumulate heat. If the outside temperature is 37 ° C, that of a rail can exceed 55 ° C and even reach 70 ° C in a heat wave ... The expansion of the steel may deform the track.
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On electrified lines, train power cables also tend to relax under the effect of heat. They risk touching the roof of the train, causing an electric arc, and the pantograph (the bow used to collect the current) can tear the catenary.
Without air conditioning, "the train will not leave"
During the summer, the agents responsible for the maintenance of the tracks and catenaries multiply the surveillance rounds on foot, one explains to the SNCF. They mainly occur at the time of day when the temperatures are the highest.
In the event of a proven risk, SNCF prefers to slow down its trains, particularly TGVs. It is also necessary to watch the embankments around the tracks, where fires can be set off by sparks as trains pass.
On the equipment side, a specific maintenance operation, called " ATS " (for " other systematic work before the hot season "), is carried out every year before summer, between April and June.
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The confinement disrupted the activities of the workshops, but all the trains were able to be revised in time, we assure the management of the SNCF. With this year paying particular attention to the maintenance of air conditioning filters, coronavirus is obliging.
" If the air conditioning does not work, the train will not leave ", assured in a recent interview the CEO of SNCF Voyageurs Christophe Fanichet. A specific “ hotline ” has been set up to respond to agents in the event of an air conditioning problem. All TGV and Intercités are air-conditioned, as are 96% of TERs and 61% of trains in the Parisian suburbs.
Water bottles and white paint
To assist travelers in the event of an incident, the SNCF has placed strategic stocks - regularly replenished - in stations throughout the country: 500,000 50-centiliter water bottles, 100,000 meal boxes, 65,000 snack boxes ... Water packs are also loaded on board the trains.
In the event of a stop during the journey, a device called " Distrib'Bar " provides for the distribution of non-alcoholic drinks at the bar. After an hour of delay if the air conditioning is broken and after two hours if it is working properly.
To complete the system, SNCF Réseau has started installing sensors on its tracks to monitor the temperature in real time. " The reliability of the device will continue in 2020 ", indicates the company.
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Less technological against the heat wave, a lick of paint? Following the example of the Basel trams and the Rhaetian Railways (RhB) in Switzerland, the Austrian, Swiss, German and now Belgian companies -ÖBB, CFF, Deutsche Bahn and Infrabel- wonder whether it would not be relevant to paint the rails white. A study by the Swiss Federal Institute of Technology in Zurich has indeed shown that painted in light colors, they are up to 7 ° C cooler.
SNCF had tested such a device a few years ago, but had not judged it sufficiently effective with regard to its cost, qualified a spokesperson. In addition, the company " since 2003 modified the design of the tracks so that it can withstand 6 ° C more in the rails ", which allows them, on the most recent or renovated lines, to withstand the temperatures encountered. on the Egyptian network, he says.